Here is some general info and year to year changes on the engine coolant, engine oil, automatic transmission and power steering fluid cooling systems.
On Police and Towing package cars an engine oil cooler is standard equipment. It appears the engine oil cooler was also available for some Limo package cars as well (Town Car).
This cooler is an Oil-to-Water type, cooling the engine oil with the engine coolant. THe cooler is mounted in-line of the lower radiator coolant hose (unique hose used)
Oil is delivered and returned from the cooler using hydraulic oil hoses. The cooler end has a pinch bolt design with 2 o-rings on the end of each hose fitting.
The engine block oil filter adapter is unique for those w/ oil cooler. The oil lines connect to the adapter using spring-lock couplings. The hose ends use female spring lock couplings. The male spring lock couplings thread into the oil filter adapter and use a 1/2" NPT thread. Each male spring lock coupling uses 2 o-rings.
On the spring lock/engine end of each hose is a small color coded section indicating hot/supply or cold/return. The return line has a blue section, the supply line a red section.
The part number for the O-rings used on the oil cooler hoses is YF-2371 which is a pack of 6.
Vehicles w/o Police or Towing package do not use an oil cooler, and have a one-piece lower radiator coolant hose.
On Police, Towing Package, Handling & Performance Package (HPP), Touring Package (1992 Crown Victoria Only), and Limo package a small, two-pass oil-to-air tube and fin style power steering cooler is used. This cooler is plumbed inline of the power steering reservoir return line (3/8" i/d)
All others do not use a cooler.
Cooler/Power steering hose routing:
All models use a radiator-tank mounted oil-to-water ATF heat exchanger. This transfers heat from the transmission fluid to the engine coolant. The transmission fluid lines are 5/16" metal tubing and go directly to the exchanger/cooler without any rubber line/hose sections.
On Police, Towing Package, and Limo package a small, external two-pass oil-to-air tube and fin style ATF cooler is plumbed inline of the ATF radiator exchanger/cooler return line. A section of 5/16" i/d rubber hose is used for both supply and return to the cooler.
Cooler line routing:
As with all years, a mechanical water pump is used.
A shrouded mechanical fan-clutch and blade is used for radiator airflow. It is rumored that some '92-'97 Towing and Police package cars had an improved (thicker) radiator and fan blade/impeller.
On 1995-1997 models, an auxiliary electric cooling fan was added and the shroud re-designed to mount the fan and have a sliding access panel on the bottom. This fan operates when the a/c is engaged, or when engine coolant temperature is high (212 degrees if I recall correctly)
The electric fan uses "s" shaped blades for reduced noise, and a 16" overall blade impeller diameter. The motor is single speed and the circuit is relayed and fused for 50amps.
This electric fan is not suitable as a primary engine fan, so if you want to run an electric fan for a little more horsepower plan on purchasing a higher CFM rated fan.
The '95-'97 aux fan temperature turn-on is adjustable within the PCM if you have an xCalibrator 2 reflasher, or dealer-access NGS system.
The engine coolant reservoir/recovery/degas/overflow tank is mounted on the RH fender apron/liner. It is a transparent composite material and is the same for all '92-'97. In '95, the coolant cap was revised to the current black plastic style. All caps are rated for 16psi.
Like '92-'97 models, this only applies to CVPI, and Limo (some). The Towing package had since been discontinued. The oil cooling system remained mostly the same, however, the spring lock couplings were elimintated and the oil filter adapter revised. The oil cooler lines are now retained using the same method as the cooler-end - a pinch bolt with both smooth male hose-ends using 2 o-rings to seal to the oil filter adapter's inlet/outlet bore(s).
For 1998, a new stacked-plate type oil-to-air cooler was developed. This cooler mounts between the A/C condensor and radiator and is used on ALL models. This cooler is a dual circuit design, also cooling the ATF (see below). Like the '92-'97 power steering coolers, it is plumbed inline of the 3/8" power steering reservoir return line. The reservoir was also relocated to a bracket on the engine front timing cover and utilizes a non-serviceable paper element filter.
As mentioned above, a new dual circuit oil-to-air stacked plate cooler was developed to cool both the transmission and power steering fluid. It is mounted between the radiator and A/C condenser. The ATF section of the cooler is roughly double the size of the power steering section. The ATF cooler also features a small thermostatic bypass valve with external housing to regulate ATF temperature. This thermostat starts to open at 180 degrees (thanks SteveS for temperature specification)
Like the rest of the cooler, the thermostat housing is aluminum. The cooler inlet/outlet lines, and the transmission cooler supply/return lines go to directly to the thermostat housing. When the thermostat is closed, ATF is recycled back through the housing to the cooler return line. When open, ATF flows through the cooler.
The ATF/Power Steering cooler is manufactured by Long, who also manufactures the stacked plate coolers for B&M performance (though the designs are much different)
The cooler supply/return lines are 5/16" metal tubing from the transmission until they near the radiator. From there the tubing has hose nipple ends and 5/16" i/d hose is used to the ATF cooler thermostat inlet/outlet.
03-05 Cooler (nearly identical to '98-'02)
The mechanical and electric fan combo used on '95-'97 is replaced in favor of a single electric fan and shroud. This fan uses a 16" overall diameter impeller and a dual speed motor. The PCM controls the low and high speed operation based on engine temperature and A/C usage.
The fan wiring was slightly revised for 2001 model year to resolve a
The coolant reservoir/recovery/degas/overflow tank was relocated to the top RH side of the electric fan shroud.
A new feature for 1998 is the Fail-Safe-Cooling system. This uses a separate temperature sensor mounted to the LH cylinder head, allowing accurate readings should there be a large coolant loss.
Service manual quote on system operation:
"If the temperature exceeds approximately 121ºC (250ºF), the powertrain control module disables four fuel injectors at a time. The powertrain control module will alternate which fuel injectors are disabled every 32 engine cycles. The four cylinders that are not being fuel injected act as air pumps to aid in cooling the engine.
If the temperature exceeds approximately 166ºC (330ºF), the powertrain control module disables all of the fuel injectors until the engine temperature drops below approximately 154ºC (310ºF).
If the engine reaches critical temperature, the following happens:
The coolant temperature gauge pointer will read fully hot at approximately 121ºC (250ºF)"
Carry-over from 1998-2002. Hoses slightly lengthened.
Carry-over from 1998-2002 design. Cooler inlet/outlet lines slightly changed (bends). Reservoir re-located to top LH side of electric fan shroud.
Carry-over from 1998-2002 design. Cooler inlet/outlet lines slightly changed (bends).
Electric engine fan now uses variable speed control module, mounted to fan shroud, to regulate fan speed using input from PCM. Fan shroud mounting revised.
Carry-over from 2003-2005.
Stacked-plate dual circuit external cooler has been decontented. Power steering fluid now cooled using a long two pass tube-and-fin aluminum oil to air cooler mounted in front, and extending the entire width of the A/C condenser. Plumbed in same fashion as all years prior.
Stacked-plate dual circuit external cooler has been decontented. Automatic transmission cooler now incorporated to the lower section of the A/C condenser.
A thermostatic bypass valve is still used, temperature rating assumed carry-over. Cooler is still an oil to air design, but appears to be a tube-and-fin type cooler.
Cooler supply/return lines revised. Thermostat housing is threaded, metal 5/16" tubing connects directly to thermostat block inlet/outlet with fittins. A section of rubber line is used between these metal tubes and the 5/16" metal tubing extending to the transmission.
Electric fan revised. "s" Blades/impeller have much less curve and are shallower. Motor appears slightly smaller. Motor 'basket' revised and bracing removed.
The reduced blade curve and depth substantially increases fan noise when operating. Overall design is less efficient and there have been overheating concerns resulting in a TSB being issued. Solution is to replace the fan with a new(er), revised unit.
Engine Coolant Temperature (ECT) gauge eliminated from front coolant crossover. Cylinder Head Temperature (CHT) sensor now sole engine temperature sensor.
06+ fan pictured on LH side:
Hoses for all cooling systems are clamped using constant-tension spring clamps, with exception to air conditioning and engine coolant when ordered w/ silicone hoses.
Severe-Duty Silicone engine coolant hoses were available as optional equipment for all 1992+ Police Interceptors and with some export packages. These are easily identified by their bright, baby blue color. Those ordered w/ silicone hoses use lined stainless steel worm drive "aircraft" clamps, instead of the normal spring clamps.
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Page last updated: 7-20-2008